<template>
  <div id="root">
    <hr class="one" />

    <h2> ToDoList 先搭建整体结构</h2>

    <div class="todo-container">
      <div class="todo-wrap">
        <MyHeader :addTodo="addTodo" />
        <MyList :todos="todos" :checkTodo="checkTodo" :deleteTodo="deleteTodo" />
        <MyFooter :todos="todos" :checkAllTodo="checkAllTodo" :clearAllTodo="clearAllTodo" />

        <img class="img" alt="example" :src="require('@/assets/static/img/vue_todeList_data.png')" height="200px">


      </div>
    </div>
  </div>
</template>
案例
<script>
import MyHeader from './MyHeader'
import MyList from './MyList'
import MyFooter from './MyFooter.vue'

export default {
  name: 'App',
  components: {MyHeader, MyList, MyFooter},
  data() {
    return {
      //由于todos是MyHeader组件和MyFooter组件都在使用，所以放在App中（状态提升）
      /* 写死数据
       todos: [
           {id: '001', title: '抽烟', done: true},
           {id: '002', title: '喝酒', done: false},
           {id: '003', title: '开车', done: true}
         ]*/
      //由于todos是MyHeader组件和MyFooter组件都在使用，所以放在App中（状态提升）
      todos: JSON.parse(localStorage.getItem('todos')) || []


    }
  },

  /*
  * 在父组件中 创建公用方法，供子组件使用
  * */
  methods: {
    //添加一个todo ，	操作data()中的数据
    addTodo(todoObj) {
      this.todos.unshift(todoObj)
    },
    //勾选or取消勾选一个todo
    checkTodo(id) {
      this.todos.forEach((todo) => {
        if (todo.id === id) todo.done = !todo.done
      })
    },
    //删除一个todo
    deleteTodo(id) {
      //直接过滤掉 => 过滤条件
      this.todos = this.todos.filter(todo => todo.id !== id)
    },
    //全选or取消全选
    checkAllTodo(done) {
      this.todos.forEach((todo) => {
        todo.done = done
      })
    },
    //清除所有已经完成的todo
    clearAllTodo() {
      this.todos = this.todos.filter((todo) => {
        return !todo.done
      })
    }
  },
  // 监视 todos 并存到localStorage
  watch: {
    todos: {
      deep: true,//深度监视
      handler(value) {
        localStorage.setItem('todos', JSON.stringify(value))
      }
    }
  },
}
</script>

<style>
/*base*/
body {
  background: #fff;
}

.btn {
  display: inline-block;
  padding: 4px 12px;
  margin-bottom: 0;
  font-size: 14px;
  line-height: 20px;
  text-align: center;
  vertical-align: middle;
  cursor: pointer;
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.2), 0 1px 2px rgba(0, 0, 0, 0.05);
  border-radius: 4px;
}

.btn-danger {
  color: #fff;
  background-color: #da4f49;
  border: 1px solid #bd362f;
}

.btn-danger:hover {
  color: #fff;
  background-color: #bd362f;
}

.btn:focus {
  outline: none;
}

.todo-container {
  width: 600px;
  margin: 0 auto;
}

.todo-container .todo-wrap {
  padding: 10px;
  border: 1px solid #ddd;
  border-radius: 5px;
}
</style>
